   [:pre (syntaxify (src-for-names defs))])
 
 (defn demo-component [props]
-  [:div.example
-   [:h3 "Example"]
-   [(:comp props)]
-   [:h3 "Source"]
-   [src-for props]])
+  [:div
+   (when (:comp props)
+     [:div.demo-example
+      [:h3.demo-heading "Example"]
+      [(:comp props)]])
+   [:div.demo-source
+    [:h3.demo-heading "Source"]
+    [src-for props]]])
 
 (defn simple-component []
   [:div

   created components, without resorting to React's lifecycle
   events."]])


(defn bmi-demo []
  [:div
   [:h2 "Simple BMI calculator"]
   [demo-component {:comp bmi-component
                    :defs [:ns :calc-bmi :bmi-data :set-bmi :slider
                           :bmi-component]}]])

(defn demo []
  [:div
   [:h1 "This will become a demo"]
   [intro]
   [managing-state]
   [bmi-demo]
   [:p "WIP"]])


(defn counting-component []
  [:div
   "The atom " [:code "click-count"] " has value: "
   @click-count ". "
   [:input {:type "button"
            :value "Click me!"
            :on-click #(swap! click-count inc)}]])
